Trying to figure out why the "on option" for fan only on thermostat is not working. We moved in this house in december, so we only used the heating so far. The house is quad with 2 furnaces and 2 ac units. Since is not hot enough for ac i just tried to use the fan only option, so i put the heat and ac on off. One fan works, one doesn't, but the ac works on both units. We checked the wires on the wall, for the thermostat, they are all conected. Any sugestions? By the way, my hubby turned the pilot light off, for both furnaces, i don't know if it has anything to do with that.